Means and method of preparing printing plates



H. H. POWERS MEANS AND METHOD OF PREPARING PRINTING PLATES Dec. 6, 1927.

Filed Sept, 4, 1924 4 Sheets-Sheet l ZN 3 M Dec. 6, 1927 H. H. POWERS MEANS AND METHOD OF PREPARING PRINTING PLATES 4 Sheets-Sheet 2 Filed Sept. 4, 1924 I erolor: er'erifin P0608715,

Dean 6, 192?, 11,652,9Q6 H. H. POWERS MEANS AND METHOD OF PREPARING PRINTING PLATES Filed Sept. 4. 1924 4 Sheefls-Sheet s New? Dec. 6, 1927.

H. H. POWERS MEANS AND METHOD OF PREPARING PRINTING PLATES Filed- Sept. 4, 1924 4 Sheets-Sheet 4 Jraerzflfomm Z/wzm maul Patented Dec. 6, 1927.

UNITED STATES enses PATENT OFFECE.

HERBERT E. POWERS, OF LA. GRANGE, ILLINOIS.

MEANS AND METHOD or rnnmmmo r nmrmo'zna'rns.

Application filed September 4, 1924. Serial No. 738,773.

upon which is placed a photo-negative through which is transmitted light or actinic rays for the transfer of the picture or like impression upon the sensitized surface of the plate. The latter is then suitably treated to fix the transfer and then the lines, areas and like parts thereof are treated with a resist material, such as a resinous powder known as dragons blood, the powder adhering to the surface and sides of the lines and like parts to be protected. Heating the plate will fix or fuse the powder in place. The remainder of the plate surface to which the powder does not adhere will be attacked or etched when the plate is placed in an etching bath, such as acid, the plates usually being of zinc, or zinc compositions, or copper and other like and similar substances. The etching fluid will dissolve the unprotected surface parts of the plates to a. certain depth and when cleaned and dried, may be again subjected to the dragons blood powder treatment.

In applying the powder it has generally been done by covering the plate surface with the powder and brushing the powder, usually with a hand brush, across the surface of the plate in one directio n. The larger per centage of the powder is brushed off the plate and the remainder is thus piled against one side of the lines or parts to be protected, as well as upon the surfaces of such lines or parts. The plate was then heated to fix or fuse the powder andthen cooled in running water. The cooling in' this way usually caused the plates to buckle or warp, the subsequent mechanical flattening of the plates usually resulting in considerable waste.

' Then the plate, again by hand operations,

was brushed With the powder in a direction transversely to that previously used and again heated and cooled. This was continued until the powder was applied four times in four different directions. Then the plate was placed in the etching bath. Further etchings or bites were made depending upon the depth of material to be removed, was obtained, each bite or etching treatment being alternated with the previous four bruslnngs and beatings, and subsequent coollngs.

Such a process required a large amount of time, much handling by the operator, the results depending upon and varying with the etliciencly of the operator and involved conslderab very high price, and with the attendant adboring and collecting of the powder to and upon the clothes and person of the operator, such as in his eyes, mouth, ears, hair, lungs e waste of powder, which sells at a and other resplratory organs. The powder would also spread about the shop, room or the like and collect upon about everything in the vicinity.

The brushing of the powder so that it will pile against the sides of the lines and parts to be protected, very much like snow drifts against a fence or wall, requires considerable ingenuity and it is impossible, in manual operat1ons,with a'brush, to apply the correct amount of powder and obtain uniform results, the piling generally being too little or too great and the consequence being a more or less irregular and inclined side wall to the line or area to be protected. Moreover, there generally always remain stray particles of powder on the parts to be etched out, which cause pin points and the like. To remove these requires the mechanical operation of gouging and rabbeting with suitable gouging and rabbeting tools.

By the present invention the operations are carried outmechanically, preferably in a unitary machine, and the powder is confined to the spaces or zones of operation or treatment wit IOUt any loss of the powder or spreading aboutthereof. The application of the powder is effected in the most eflicient manner and at the proper angle to produce the piling of the correct amount against the sides of the lines or areas to be protected, so

ling and warping of plates and the attendant;

waste thereof. The cooling is preferably effected by a stream of air, although other fluids may be used if desired. Inasmuch as the plate has not been heated, but only the owder on the surface thereof, little cooling is necessary, and the return of the plates to be powdered for transverse piling, is accordingly hastened.

The powder is preferably circulated in a way such that the powder not used on the plate is immediately drawn away and conveyed to a collecting reservoir where it may be distributed, rather than piled up in a single pile, by suitable means, such as baffles and means may be provided for ready release of the air utilized to convey the material to the reservoir, such as through pervious pockets or cells. Since the powder has the characteristic of adhering tightly to objects with which it contacts, the pervious means may soon clog and to avoid this, the pockets or cells may be made to vibrate, as by allowing them to contract and then suddenly stretching them taut so as to snap the powder from the surfaces thereof, the powder then falling into the lower part of the reservoir, This is only necessary at infrequent intervals and may be effected by hand operated mechanism, although power operated means are comprehended by the invention for the purpose of accomplishing the desired results. The collected powder may also be stirred, preferably continually to prevent the packingand to be in condition for the pneumatic conveying of it to the owdering zone when the control mechanism 1s 0 erated, such as the valve in a .conduit leading from the reservoir to a blower and projecting nozzle, the latter being of utility to direct the air and powder upon the surface of the plate at the angle requisite to effect the proper piling of the powder against the sides of the parts to be protected.

The fixing or fusing of the powder on the plate is by way of heating, and preferably in a heating chamber with the heating means, such as burners, located above and suitably proximate to the surface of the plate when it is located in or moved into the chamber. To economize fuel supply, the heater may have a pilot light and the main supply may have a control valve capable of operation by the means carrying the plate into and out of the heater, to open and close the valve respectively, the pilot acting to ignite the burners when the fuel is turned on and the plate is in the heater. To assure good combustion, air may be supplied through a valve controlled conduit into the upper part of the heater, the latter being preferably provided at its lower part, as at the sides thereof, with openings for the free exit of the products of combustion. The heat is preferably applied downwardly against the surface of tlie plate rather than upwardly through the p ate.

In the cooling zone the means for supplying the air to the powdering zone and for exhausting the surplus of powder therefrom, may be constructed with valve controlled passages and operating mechanism for the valves for automatically effecting the flow of cooling air upon-the plate after leaving and before moving to the powdering zone or chamber, the means carrying the plate being preferably provided with means, such as spring pressed cam-pawls or similar elements, for actuating the valve operating mechanism when the means for carrying the plate is moved.

Inasmuch as the powder is applied first in one direction across the surface of the plate. and then in a direction transverse to the former direction or at right ,angles thereto, until the powder has been applied in four directions, the means for carrying the plate is preferably provided with a turntable or the like with mechanism on the table and the support of the machine, cooperable to give the table a quarter turn between the powdering operations, this being done preferably after the fixing or fusing of the powder in the heater and as the plate is leaving the heating device, although it may occur at any other point of movement of the carriage and the plate, as for example, just before entering the heater or just before entering the powdering zone or chamber.

The invention also comprehends other objects,.advantagcs, and capabilities, as will later appear and are inherently possessed by the invention, it being understood that the specific device herein described and shown upon the drawing, is merely illustrative of the invention. the latter not being limited to the specific disclosure made but comprehending other details. arrangements of parts and constructions without departing from the spirit of the invention.

In the drawings, illustrating an embodiment of the invention, Fig. 1 is a view in side elevation of a machine constructed in accordance with the invention: Fig. 2 is a top plan view of the same; Fig. 3 is a. top plan view of a plate carriage and turn.- table, with parts of the powdering chamber in fragmentary section and also showing,

loo

diagrammatically, the automatic means and operation for turning the turn table a quarter turn; Figs. 4, and 6 are fragmentary sectional views of the carriage and turntable; Fig. 7 is a longitudinal vertical section through the owder collecting reservoir and the pow ering chamber; Fig. 8 is a transverse sectional view of the collecting reservoir; Fig. 9 is a detailed view, partly in section, of one of the pockets or cells of the collecting reservoir; Fig. is a longitudinal sectional view of part of the powdering means and powder cleaning device; Fig. 11 is a. perspective view, partly in section and partly in diagram of the valve control mechanism and the. means on the carriage for actuating the same; and, Figs. 12 and 13 are respectively top plan and side elevational views of the latch for causing the quarter turn of the turn table.

Referring now more particularly to the drawings, the embodiment chosen to illustrate the invention is shown as comprising a supporting frame or support 1 having legs 2 carried on casters 3 and provided with sheet metal side and end panels 4. Upon the top 5 of the support, which may also be of sheet metal, are located and secured a pair of rails 6 over and along which is capable of traveling acarriage 7 having wheels 8 arranged and adapted to operate on the rails 6. The carriage is capable of moving from one end of the machine to the other end thereof along the rails as clearly shown in Figs. 1, 2 and 3 of the drawings.

To the ends of the carriage 7 are secured the ends of a cable or rope 9 capable of passing over pulleys 10 and 11 rotatably mounted in brackets 12 and 13 secured, in any suitable manner, to one end of the support 1, and over another pulley 14 rotatably supported in a bracket 15 secured to the other end of the support 1, as clearly shown in Figs. 1 and 2 of the drawings. The cable continues about a hand operated drum 16 carried by a shaft 17 rotatably mounted in a side wall 4 of the support and to the outer end of which shaft is secured a hand wheel 18 provided with a handle 19 by which the hand wheel and drum 16 may be rotated as desired. The cable 9 preferably has one or more turns about the drum whereby traction may be effected. From the above construction it will be apparent that the carriage may be caused to travel along the rail, as for example, from the left to the right hand end of the machine by a right hand rotation of the hand wheel 18 and drum 16. and a travel of the carriage from the right hand end of the machine to the left hand end thereof by a left hand rotation of the wheel and drum.

The carriage 7 is preferably made of sheet metal and hollow and arranged to receive a rotating turn-table 20 carrying a grating 21 a hf pp r end of he turn-tab e and upon and 6 of the drawings.

which a plate, to be treated, may be placed. The turn-table is provided, at several points arranged in a circle, with wheels or rollers 22 each having a tire portion 23 and a flange portion 24 bearing respectively laterally and downwardly against a race-way portion or track 25 formed in the lower wall 26 of the carriage 7. The race-way or track portion 25 is preferably circular and the wheels 22 stantially present'the top surface of the turntable level or even with the top surface of the carriage 7, as clearly shown in Figs. 3, 4, 5 At suitable points along the periphery 28 of the turn-table are provided a number of recesses or depressions 29, preferably at 90 degrees apart, and into which may engage a ball 30 normally pressed into place by a spring 31 included in a cap- 32 secured to a side wall 33 of the carriage 7. When the turn-table is rotated, as for example a quarter turn, one of the depressions 29 will arrive opposite the spring pressed ball 30 so that the latter will enter into the recess or depression 29 and normally resiliently lock or hold the turn-table from further rotation, yet not preventing the forcible rotation of the table when it becomes desirable to do so, which will be later more fully explained. See

Fig. 6 of the drawings.

At each time that the carriage is caused to move from the left hand to the right hand end of the machine and then return to its original position, means is provided to cause an automatic turning of the turn-table a quarter turn so that the plate carried upon the grate 21 may be presented for movement and treatment in a direction transverse to or at right angle to its previous movement and treatment. This turning of the table is effected by a latch arrangement 34 located near one of the rails 6, see Fig. 3 of the drawings, and which is shown in detail in Figs. 12 and 13 of the drawings. This latch arrangement has a base member 35 suitably secured to the top 5 of the support near the front rail 6 of the device and has a bearing member, 36 carrying a pivot bolt 37 to which is rotatably mounted a cam lever 38 having a cam surface 39 anda cam slot 40 of generally S or Z-shape and having lateral openings or throats 41 and 42 as clearly shown in Fig. 12 of the drawings. The cam portion 38 is normally held in upper or horizontal position by a spring 43 reacting between the members 38 and 35, as clearly shown in Fig. 1 3 of the drawings. Cooperating with this cam are pins 44 connected to the bottom of the turn-table 20 at four different points and arranged in a circular path when the turn-tab e is rotated. The positions of these pins are designated by characters A, B, C and D, as referring to the first, second, third and fourth pins in their relative positions as they are operated upon by the cam device 34 and as shown in their different positions in dotted lines in Fig. 3 of the drawings. When the turn-table is located so that the spring pressed ball is properly located in one of the recesses 29, the pins A, B, C and D will be in the positions shown at the left hand end of Fig. 3 and designated by the characters A, B, C and D. Upon moving the carriage to the right the pins D and A will successively engage with a beveled or inclined face 45 on the upper member 39 of the cam mechanism or latch? 34 and will cause the cam member 38 to be depressed against the compression of the spring 43, thus permitting the carriage to pass on to the right hand end of the machine without any turning efiect of the turn-table. When the carriage is caused to move in a. reverse direction the pin A'will" first contact with the inner end of the cam surface 39' at substantially the point 46 as tion of pin 0 and so on about the circle.

' The successive positions of the pins and the turn-table are diagrammatically shown in dotted lines,in Fig. 3 of the drawings. The

' position 47 shows the turn-table before the pin A engages with the cam; the position 48 showing the position of the turn-table just as the pin A engages with the cam surface 39; the position 49 showing the same when the pin A isentering the throat 41 and the position 50. showing the same when the pin A is leaving the throat 42 and when the pin B has assumed the position that pin A formerly had. Further movement of the carriage to the left will not turn the turn-table, but as the pin reaches the throat 42 and about to leave it, the turntable shall have turned with a depression 29 opposite the spring press ball 30 so that the latter will spring into it and normally hold the turn-table in its new and turned position.

At the left hand end of the machine and upon the top '5 is arranged a powdering chamber or zone in the form of a closed easing into which the carriage may travel.

of the casing. The left hand end of the casing tapers to form an outlet 54 connected with an intake 55 of an exhaust blower or pump 56 operated by a motor 57 suitably connected to the pump to operate it at a high speed. The pump has a discharge conduit 58 leading downwardly and then laterally into an end of a collecting reservoir 59 arranged beneath the top 5 of'the machine. The other end 52 of the casing is provided with an opening 60 through which the earriage 7 may enter into or ass from the easing. To this end 52 of the casing are also secured supporting brackets 61 having bearings 61 for supporting pintles 62 of hellcrank arms 63. To an end of the arms 63 is rotatably mounted a brush 64 by means of shaft 65. The other end of the arms 63 extend upwardly and carry adjusting screws 66 threaded through portions 67 with the end of the screws engaging with cam surfaces 68 supported upon or forming flanged portions on an upwardly extending part 69 of the brackets 61, all as clearly shown in Fig-.10 of the drawings. By loosening the screws 66 the arms 63 may be moved so as to raise or lower the brush 64 toward or "from the surface of the plate carried on the carriage traveling beneath the brush. Vhen in the adjusted position the screws 66 may be tightened against the cam surfaces 68 so as to hold the brush in desired position. Also extending throughthe opening 60 is the lower end or nozzle portion of a powder discharge 70 having a narrow elongated slot or orifice 71 capable of discharging air and powder at an acute angle to the surface of the plate resting upon the carriage 7, as clearly shown in Fig. 10 of the drawings. Overhanging the orifice 71 is preferably provided a lip or flange 72 for confining the stream of powder and air projected from the orifice to the space immediately above the surface of the plate carried by the carriage 7. The nozzle 70 is preferably supported in adjusted position by means of brackets 7 0 having flanges secured to the top of the nozzle 70, and slotted arms adjustably secured to the end wall 52 of the chamber or casing, by means of suitable bolts extending through the slots of the bracket arms. By loosening the bolts the brackets '70 together with the nozzle 70 may be adjusted as to height, and then when the bolts are tightened the nozzle, together with the brackets, will be held in adjusted position. The lip may be provided with a head 73 for reinforcement. An electric light 74 may be located above the transparent door 53 so as to transmit light within the interior of the casing.

Over the top 5 and intermediate the ends of the machine is located a blower plant comprising a pair of blowers 75 and 76 mounted upon a common shaft with and driven by a motor 77; the motor and the blowers bein as a unit, supported upon a stand comprising legs 78 at both sides of the machine and connected horizontal membars 79 and 80, the lower ends of the legs 78 being suitably secured or fixed to the frame 1 of the machine. The blower 75 discharges into a conduit 81 flaring-ainto a wide nozzle 70 in which is rovided the orifice 71 as previously descri ed and .which is shown in detail in Fig. 10 of the collecting reservoir and communicating with it in the manner hereinafter to be more fully described. The other blower 76 has its intake open to the "atmosphere of the room and discharges into a conduit 88a-lso flaring into a nozzle 89 having a narrow and elongated orifice 90 located to discharge a sheet of air over the ends of the bristles of the brush 64. The air blown through the nozzle 89 is for the purpose of removing the particles of dust adhering to the bristles of the brush, as the latter is caused to rotate, and projecting such particles into the space of the chamber in which the powdering takes place. These particles of dust are then drawn by the suction blower 56 and returned to the collecting reservoir 59. The end of the nozzle 89 is preferably provided with adjusting screws 91 suitably secured to the nozzle 89 and passing through suitable apertures in flange extensions 92 of the cam members 68 and held in adjusted position by nuts 93, one of which will act as a lock nut. When it is desired to raise or lower the nozzle 89 with relation to the surface of the brush 64, it is only necessary to turn the nuts 93 to effect the desired relation of the nozzle 89 with reference to the brush For the purpose of driving the brush 64 the Shaft of it is connected through suitable gearing 94 to a shaft 96 connected in turn to suitable gearing 97 to the outer end of the shaft of the motor 77, the drive being effected from the motor shaft to the brush as clearly shown in Figs. 1 and 2 of the drawings. The discharge conduit 88 of the pump or blower 76 is preferably provided with a branch outlet 98 for directing a stream of air downwardly upon the plate carried by the carriage 7 when the latter is in position underneath the discharge outlet 98. The purpose of this is for projecting cooling air upon the surface of the plate after the same has been heated and moved from the heating apparatus. The passage of air through the outlet 98 or to the nozzle 89 is controlled by a valve 99 (see Fig. 11 of the drawings) which in one position will open the passage of air to the nozzle 89 and close the passage of air through'the discharge 98, and in another position will cut off the flow of air into the nozzle 89 and open up the passa e through the discharge nozzle 98.

The va ve 99 is secured to a shaft 100 supported at the outer end thereof in a bracket 101 secured to one of the legs 78 of the stand upon which the blower plant is supported. To this shaft is fixed an arm 102 carrying a pin 103 against which may operate or contact a spring pressed pawl or cam member104 pivotally connected to a bracket 105 secured to the top of the carriage 7. The pawl has a spring 106 react-.

ing against the face of the brackets 105 and an arm 107 of the pawl :to normally hold it in upright position, the pawl being limited in movement by a stop arm 108 normally bearing against the top surface of the carriage 7 as clearly shown in Fig. 11 of the drawings. When the table is moved in one direction, as from the powdering to the heating zones, the cam 104 will engage with the pin 103 to be rocked and compress the spring 106, the table and pawl passing on without operating the valve mechanism connected to the arm 102 and pin 103, but when the carriage 7 is moved in the opposite direction the pawl 104 engages the pin 103, and by reason of the limit stop 108 bearing against the top surface of the carriage 7, and thus hold the pawl 104 in fixed position, the pawl 104 will effect a movement of the pin 103 together with the arm 102 and shaft 100 so as to operate the valve 99 from a position where it closes, the nozzle 89 to a position where it closes the discharge 98 and opens the nozzle 87.

The shaft 100 also has secured to it an arm 109 slotted to receive a pin 110 connected to a bell crank lever 111 rotatably supported upon a projectin portion 112 of the bracket 101-and provide with a depending arm 113 carrying a contact pin 114. This pin 114 is operated on by a pawl 115 of the same construction as pawl 104, it comprising an arm 116 against which reacts a spring 117 bearing against the base of a bracket 118 secured to the top surface of the carriage 7 but laterally out of alinement with the pawl arrangement 104. The pawl 113 also has a stop or limiting arm 119 normally bearing against the top surface of the carriage 7: When the carriage is moved in one direction.- the arm or pawl 115 will engage with the pin 114 and be moved, while compressing the spring 117, to pass by the pin 114 without effecting any movement of the arm 113 and the parts connected to it, but when the carriage is moved in an opposite direction the pin 115 engages the pin 114 and by reason of the limit arm 119 bearing against the top surface of the carriage 7, will effect a valves 125 movement of the pin 114 together with the arm 113 and the pm 110 upwardly to swin the arm 109 upwardl and turn the shaft 100 so as to swing t e valve 99 from its closing position with reference to the discharge 98 to a closing position with reference to the nozzle 89.

At the right hand end of the machine is located a heating device comprising preferably a sheet metal casing 120. closed at the top and opened at the bottom and spaced from the top 5 of the support and supported by legs 121 suitably secured to the sides of the casing 120 and the side walls of the support 1. In the upper part of the casing 120 are located a plurality of gas burners 123 connected to a main 124, each burner being individually controlled by hand operated the valves 125 being also provided with suitable air regulating devices 126 as is usual. The main 124 extends about the end of the machine and is provided with a spring operated valve 126 having a lever 127 arranged to extend within the space of the heating device and in the path of movement of the carriage 7 such that when the carriage 7 has been moved to the right hand end of the machine, the end wall of the carriage may engage with the lever 127 and cause it to move from the position shown in full lines thereof to the position shown in dotted lines thereof in Fig. 2 of the drawings, whereby the valve 126 will be opened. When the carriage 7 is moved away from the right hand end of the ma-' chine, the valve 126 will be closed automatically by a spring surrounding the stem of the valve: and return the lever or arm 127 from the dotted line position to the full line position thereof in Fig. 2 of the drawings. In this way the gas may be turned on or turned off automatically when the carriage arrives or is moved from the heating device and thus economize the fuel by preventing the combustion of the fuel to the full extent at all times. From the main 124 leads a pilot tube 128 provided with a number of pilot burners or orifices 129 for providing pilot flames within the chamber. This flame is normally lighted at all times, and when the fuel or gas supply is conveyed to the burners 103, the pilot flames will ignite the same so that the burners may operate at full load during the time the carriage and plate is in the burner chamber. At the uper part of the chamber 120 is located an air inlet tube 130 communicating at one end thereof with the upper space of the chamber 120, and extending beneath the blower plant and having a flared opening 131 at its other end for the intake of air from a stream passing upwardly through an opening or screened port 132 formed in the top 5 of the table support of the machine. The screened opening 132 communicates with the upper part of the powder collector and is an outlet for the compressed air in the collector when the same is operated to bring the pow der therein. The stream of air passing through the screened opening 132 will be directed to the opening 131 and pass through the conduit 130 into the heating chamber to supply air or other supporter of combustion to the burners therein. The heated air in the chamber 120 as well as the radiant heat from the burners will be directed downwardly toward the plate carried upon the carriage and over the surface of the same and out through the space between the chamber 120 and the top surface 5 of-the machine, thus affording a free and ready outlet for the products of combustion at all sides of the heating device. In order to prevent the downward flow of the heated gases or the like passing through the grid or grating 21, especially when treating small plates, and heating the carriage parts, a plate or sheet 121' of heat insulating material, such as asbestos,is supported, in a horizontal position in the lower part of the heating device, by legs 121 fastened to the top 5. The board or plate 121" is held as close to the bottom of the carriage as possible when the carriage is in the heating zone. This restricts the possible passage of the hot gases through the narrow space between the board or plate 121' and the bottom of the carriage, and hence the hot gases will freely pass from the surface of the carriage laterally through the wide openings between top of the carriage and the lower edges of the side and end walls of the hood 120.

The conduit 130.is preferably provided with a butterfly valve 133 upon a shaft 133' connected to a controlling arm 133 connected by a link oirod 134 pivotally connected to an arm 135 rigidly secured to the shaft 100. VVhenthe shaft 100 is operated or turned at the time of operating the valve 99, it will also operate, through the link 134, the valve 133 to open and close the same at the proper instant of operation of the device which will be more fully explained later.

Referring to the feed device at the bottom of the powder collector, the valve is operated by an arm 136 connected to an arm 137 fastened to a shaft 138 operatively connected to a rod 139 connected to a hand level- 140 arranged at the front of the machine and at ready access of the operator. By operating the hand lever 140 the butterfly valve 85 may be" thrown open and the powder in the end 86 of the feed tube 87 may be drawn into the conduit .83 by the suction produced by the fan blower 75 and hence the powder will be drawn therethrough and projected through the nozzle or orifice 71 of the powdering device into the powdering chamber or zone where the plate is to be originally treated. For the purpose of preventing the accumulation and clogging of powder in the conduit 83, and to permlt of the clearing of the passage therein of the powder at the time when the butterfly valve 85 is closed, the conduit is provided wlth'an inwardly opening check-valve 83f normally having the valve seated by a spring 83 of given tension or compression, such that when the valve 85 is opened the pressure of the air in the tube 85 and the suction in the conduit 83 are such as to permit the valve 83 to remain closed but when the valve 85 1s closed, the suction in the conduit 83 wlll effect an opening of the valve 83 and the entry of atmos heric air into the passage 83 and the pump 5, so also nozzle 70, so as to clear the passages thereof of all dust that may be therein at the instant of the closing of the valve 85. By having such passages neat and clean, there will not be projected clogs or lumps of powder from the nozzle 70 when next opening the valve 85 and operating the pump 75, but the powder will be drawn from the conveyor part 86 and supplied to the plate from the nozzle in proper suspended and distributed condition.

From the above it will be noted that the powder is circulated through the machine and is confined therein so that it will not spread about the vicinity of the machine, the powder first passing from the feeding part of the collector through the blower and nozzle into the powdering chamber and then the surplus thereof exhausted through the suction blower and returned into the collecting reservoir. The latter is shown more specifically in Figs. 7, 8 and 9 of the drawings and as provided at its upper part with a plurality of cells or pockets 141 of pervious material such as cloth, canvas and the like through which air may pass but which will be of such a mesh or weave as to prevent the passage of the powder. Each pocket is preferably in the form of a tube or cylinder having an end thereof secured to a ring 142 fastened to the rim of an opening in the wall 143 of the collecting reservoir 59, and the upper end of the pocket being secured to a ring 144 carrying a conical pervious portion 145 secured at the apex thereof to a ring or eye 146. Each eye 146 is connected by a link 147 to a bell crank lever 148 pivotally supported upon cross-shafts 149 rotatably supported in the side walls 150 of the upper part of the collecting device. Each shaft 149 has acrank arm 151 secured thereto and pivotally connected at the free ends of the arms 151 to a horizontal shaker bar 152, the latter extending outwardly of the machine at one end thereof and belng pivotally connected to a lever 153 carrying a handle 154. The operator may operate the lever 153 by means of the handle 154 and cause a longitudinal operation of the shaker bar 152 and hence an up and down movement of the arms 148 and hence the upper ends of the pockets. This will first cause a contraction of the pockets and then when the levers or arms 148 are moved upwardly, so as to give the pockets a taut stretch, the powder adhering to the inner walls of the pockets will be snapped therefrom and caused to drop into the lower part of the collecting reservoir. These pockets are arranged in plurality and at the upper part of the collecting reservoir so that as the powder and air are forced into the reservoir the air may proceed upwardly through the pockets and pass therethrougl'i into the upper chamber portion 155 and thence through the screened outlet 132, the air thus passing out being free of powder. The stream of air passing through the screened outlet 132 is of utilit for supporting combustion in the heating evice as above described. The collecting reservoir is preferably supported by means of supporting brackets 156 secured to the top 5 of the device and held in position as clearly shown in Figs. 7, 8 and 9.

As the powder and air is projected through the passage 58 into an end of the collector chamber 59, if no means were provided to prevent it, the powder would be projected to the other end of the collecting reservoirand packed into a single pile, with an uneven distribution of the powder. The powder would probably accumulate to the extent of clogging the entry to some of the pockets 141. In order to'aid or serve in distributing the powder throughout the collector, the latter is provided at the lower part thereof with one or more baffles 157 and 158 so arranged that when the stream of air and powder is directed longitudinally through the upper part of the collecting receptacle, the same will impinge against the upper part of the baffles so as to cause a whirling or spreading of clouds of the powder so the same will settle into the lower portion or legs 159, 160 and 161 in more or less even level. While the powder is settling the air is passing upwardly through the various pockets 141 and to the exterior through the outlet 132. The legs 159,160 and 161 are opened at the lower ends thereof and communicate with, the feed tube 87. In this feed tube 87 is located a spiral or helical feed screw 162 operated by gear mechanism 163 operatively connected to a shaft 164, connected to gear mechanism 165 operatively connected with the shaft of the motor 57, connected to the pump 56. The tube 87 may also be provided with a hopper 166 through which additional powder may be supplied to the feed tube 88, the hopper 166, being normally closed by a cap 167. The screw 162 is operative, when it is rotated, to gradually feed the powder toward the right end of the tube, as viewed in Fig. 7 of the drawings, and toward the valve 85 which controls the feed of the powder tothe exhaust or drawing tube 83 leading to the powdering floor 75. In order to prevent the powder from packing so that it could not be readily drawn by the suction .produced in the passage 83 and the end 86 of the tube, the screw shaft is provided, in the tube 87, with reversed inclined scroll portions 168 operating with a tendency to feed the powder backward but being few in number Will not be sufficient to totally counteract the feeding action of the remainder of the screw. The portions 168 are preferably provided with a number of notches 169 for the passage of the powder to the valve In this way the powder is thoroughly stirred and prevented from packing or caking so that it Wlll be in proper and fit condition to be easily drawn by the air passing through the valve valve 85, when the latter is opened, and t0 the intake of the suction blower 75 and hence to the nozzle 70.

The motors are preferably operated electrically through a switch box 170 in which may be also located a rheostat and from which lead the conductors through the sheathing 171 passing through pipe 172 and sheathing 173, the latter including the conductors to the motor 57 and the sheathing 171 having conductors 174 leading to the motor 77. A tube 175 for conducting the conductors of the lamp as well as supporting the same may be connected as shown in Fig. 2 of the drawings, and the inlet conductors 176 may carry the current to the switch and motors as well as the lamp.

In the operation of the device and with the carriage in the powdering chamber, a plate, to be treated, is placed upon the grate 21 and then the rheostat is operated so as to start the motors, which will start to operate simultaneously, and then the operator will oper: ate the hand lever 140 so as to open the butterfly valve 85 whereby the suction blower 75 will draw powder through the conduit 83 and project the same through the nozzle 70 at an acute angle to the surface of the plate. At the same time the operator will operate or rotate the wheel 18 and drum 16 together with the rope 9 so as to cause the carriage with the plate to move to the right, as viewed in Fig. 1 of thc drawings, so that the surface of the plate will gradually pass underneath the stream or sheet of powder being projected from the nozzle or orifice 71 upon the surface of the plate. By locating the nozzle 70 at the proper angle with reference to the surface of the plate and regulating the pressure of air from the blower, the powder may be projected upon the side walls or ridges of the raised portions of the plate at the proper angle to pack or pile the powder to give the best effect when the plate is later treated by etching in the etching bath. The surplus powder will be thrown about into the chamber and will be rapidly or quickly drawn out b the exhaust blower 56 and returned into t e collecting reservoir 59, where the powder may settle and the surplus air pass through the pockets and through the openin 132.

As t e carriage proceeds to the right, the rotating brush 64 will have a very light contact with the surface of the plate for the purpose of removing all stray and foreign particles which might finally roduce pin points and the like. These particles adhere to the bristles of the brush and are carried upwardly toward the nozzle 89. Air at that time is being projected from the orifice 90 and will remove the adhering particles and project the same into the lower part of the powdering chamber and be drawn through the exhaust blower 57 and returned into the collecting reservoir 59. As the carriage proceeds beneath the discharge outlet 98, the latter is in closed position at this time so that no air can pass downwardly therethrough and destroy the piling of the powder on the plates. The carriage then next proceeds into the heating chamber 120. As it arrives at the end of its throw or movement of the ri ht hand of the machine, the right hand si e of the carriage 7 will engage with the lever 127 and cause the same to move into the dotted line position shown in Fig. 2 of-the drawings and open the valve of the fuel conduit. The gas or fuel would then proceed to the burners and be ignited by the pilot flames and immediately heat the surface of the plate. The effect of the heat is to merely heat the powder or fuse the same upon the surface of the plate without materially heating the surface portion of the plate and without any heating of the body portion of the plate. At the same time the air that is blown through the opening 132 will pass into the conduit 130 and into the upper 'part of the chamber 120 for supplying supporter of combustion and causing the heated gases to pass downwardly against the surface of the plate and out through the lateral openings beneath the chamber 120. In the meanwhile the operator has operated the arm 140 so as to close the valve and prevent further projection of the powder into the powdering zone or chamber. As the carriage was moved to the right, both pawl cams 104 and .115 operated idly by slipping by the pins 103 and 114;. It will be noted that in Fig. 11, the valve 99 is shown in the position for closing off the discharge 98.

The operator will now rotate the hand wheel 18 in a reverse direction so as to cause the carriage to travel toward the left. The first movement of the carriage will effect the release of the arm 127 so as to permit the spring of the valve 126 to close off the fuel in the burners. As the carriage proceeds to the left, a pin 44, such as that designated by menace the character A in Fig. 3 of the drawings, will contact with the cam surface 39 of the cam latch and ride along this surface to the throat 41 and then into the groove 40 and out of the throat 42, thus causing a quarter turn of the turn-table in the carriage. It will be noted that when the carriage had been moved toward the right, the pin 44 had engaged with the inclined surface 45 so as to depress the latch mechanism 34 without any action to turn the turn-table. With the turn-table now turned at 90 degrees from its previous position, it will be noted that the plate will now be presented to the nozzle or orifice 71 at 90 degrees to its previous presentation so that the powder may now be piled against the lines or ridges at right angles to the direction of previously piling the powder.

As the carriage proceeds from the heating chamber into the space between it and the powdering chamber and beneath the blower plant, the pawl 115 will first engage with the pin 114 and operate the valve mechanism so that the valve 99 will open the discharge passage 98 and close the discharge nozzle 89 and at the same time will close the valve 1 3 3 in the passage 130, so as to prevent any backflow of hot air from the heating chamber through the opening 181 toward the plate. By opening the passage 98, the blower 76 Wlll discharge cold air through this opening upon the top surface of the plate and will cool the same, particularly the fused powder thereon. As the carriage still proceeds further, the cam member 104 will then engage with the pin 103, it being in a position to engage the same by reason of its previously having been moved with the shaft when turned by the operation of the cam 115 against the pin 114. The engagement of the pawl 104 with the pin 103 will operate the valve mechanism to the position shown in Fig. 11 so as to close the discharge opening 98 and open the passage through the nozzle 89 and again open the passage 130 to the heating chamber. Further movement of the carriage will bring it into the powdering chamber where the operator may again powder the plate as in the previous case. The time consumed in performing these operations is much shorter than that heretofore required when hand operations were required. It will be noted that when the plate 1 now enters into the powdering chamber it has been turned 90 degrees from its previous position so that the powder from the nozzle may be projected upon the ridges, lines and areas of the plate, to be protected, in a direction transverse to the previous direction of powdering. The operation will be carried on in this way until the plate has been powdered from four different directions. After this the plate may be removed to the etching bath and the unprotected parts of the plate removed or etched to the desired depth. If the depth is not sufficient, the plate may again be returned to the machine and powdered as before and again returned to the etching bath for a deeper etching or bite.

Having thusdescribed my invention, I claim: 7 4

1. A device for preparing printing plates, comprisin a powdering means, a heating means, an a movable means for carrying the plate to be treated from the powdering means to the heating means, said heating means being constructed and arranged to apply heat to the powdered surface of the plate, said heating means having means cooperable with th movable means for supplying heat when the movable means has moved into the heating means and for cutting off the heat supply when the movable means starts moving from the heating means.

2. A device for preparing printing plates comprising a powdering means, a heating means, and a movable means for carrying the plate to be treated from the owdering means to the heating means, sald heating means being constructed and arranged to apply heat to the powdered surface of the plate, said powdering means having means for exhausting surplus powder from the vicinity of said plate.

3. In a device for preparing printing plates, 2. powdering device comprising means for blowing a resist powder against the surface of the plate and at an angle thereto, and means for moving the plate relative to the blowing means for progressive powdering across the face of the plate.

4. In a device for preparing printing plates, a powdering device comprising means for blowing a resist powder against the sur face of the plate and at an angle thereto. means for moving the plate relative to the blowing means for progressive powdering across the face of the plate, and means for removing surplus powder from the plate.

5. In a device for preparing printing plates, a powdering device comprising means for blowing a resist powder against the surface of the plate and at an angle thereto,

means for moving the plate relative to the blowing means for progressive powdering across the face of the plate, and means for fixing to the surface of the plate the powder remaining upon the plate.

6. In a device for preparing printing plates, a powdering device comprising means for blowing a resist powder against the surfac of the plate and at an angle thereto, means for moving the plate relative to the blowing means for progressive powdering across the face of the plate, and a rotary brush for removing surplus powder from the surface of the plate.

7. In a device for preparing printing plates, a powdering device comprising means surface of the plate. I

' 8. In a device for preparing printmg for blowing a resist powder against the surface of the plate and at an angle thereto, means for movin the plate relative to the blowing means for progressive powdering across the face of the plate, and an exhaust device for drawing surplus powder from the plates, a powdering device comprising means for blowing a resist powder against the surface of the plate and at'an angle thereto, means for moving the plate relative to the blowing means for progressive powder ng across the face of the plate, means for fixing to the surface of the plate --the powder re- "-maining upon the plate, and means for turning the plate substantially a quarter turn for the application of powder to the surface thereof transversely of the direction of the previous application of the powder thereto.

9. In a mechanism for preparing printing plates, means for moving a plate from a owdering zone to a heating zone, and means or applying a resist powder to the surface of the plate to be treated, said means comprising a projecting nozzle having a narrow elongated orifice for projecting the powder in a sheet over the surface of the plate.

10. In a mechanism for preparing printing plates, means for moving a plate from a powdering zone to a heating zone, and means for applying a resist powder to the surface of the plate to be treated, said means comprising a projecting nozzle having a narrow elongated orifice for projecting the powder in a sheet over the surface of the plate, and a lip adjacent said orifice for aiding in directing the projecting of the powder over the surface of the plate.

11. In a mechanism for preparing printing plates, means for moving a plate from a powdering zone to a heating zone, and means for applying a resist powder to the surface of the plate to be treated, said means comprising a projecting nozzle having a narrow elongated orifice for projecting the powder in a sheet over the surface of the plate, and means for supporting-the nozzle adjacent the plate for projecting the powder at an acute angle to the surface of the plate.

12. In a mechanism for preparing printing plates, means for moving a plate from a powdering zone to a heating zone, and means for applying a resist powder to the surface of the plate to be treated, said means comprising a projecting nozzle having a nar- I 7. row elongated orifice for projecting the powder in a sheet over the surface of the plate, and means for supporting the nozzle adjacent the plate for projecting the powder at an acute angle ,to the surface of the plate, and an overhanging lip on the nozzle for confining the projected sheet of powder to the proper angle for applying the same to comprising a projecting nozzle having a nar-.

row elongated orifice for projecting the powder in a sheet over the surface af the plate,-

and means for adjusting the angular relation of the nozzle and the plate.

14. In a device for preparing printing plates, a support, movable means on the support for moving a plate from a powdering zone to "a heating zone, said movable means including a turn-table upon which the plates may rest, means on the support and on the turn-table 'coo crating to effect a partial turn of the tab e when the latter is moved from the heating to the powdering zone whereby the successive powdering of the plate may be transversely to the direction of the preceding powdering of the plate.

15. In a device for preparing printing plates, a support, movable means on the support for moving a plate from a powdering zone to a heating zone, said movable means including a turn-table upon which the plate may rest, a grooved latch on the support, a pin on the turn-table and cooperable with the latch when the turntable is moved from the powdering zone to the heating zone to idly operate the latch and when the turn-table is moved from the heating zone to the powdering-zone to cause the pin to ride in the groove of the latch to effect a quarter turn of the table.

16. In a device for preparing printing plates, a support, a carriage movable over the support through powdering, heating and cooling zones and adapted to carry a plate to be treated in said zones, means for supplying air in said cooling zone and including a conduit provided with a control valve, mechanism connected to said valve for operating the same, and means on the carriage 1 for engaging with the mechanism to operate the valves whereby the air may be supplied to said zones when the carriage moves therein and to cut off the air when the carriage is moved therefrom.

17 In a device for pregaring printing plates, :1 support, a carriage movable over the support through powdering, heating and cooling zones and adapted to carry a plate to be treated in said zones, means for supplying air to the powdering and cooling zones comprising discharge outlets extending re spectively into said zones, a valve for controlling said. outlets, and means connected to the valve for operating the same to open one outlet when closing the other. means on said carriage cooperable with said valveopcrating means when said carriage is moved from the heating zone to the cooling zone to actuate the valve to open the discharge outlet for the cooling zone whereby air is supplied to cool the plate on the carriage, said means on said carriage also operating when the carriage is moved from the cooling zone to actuate the valve operating means to move the valve to closed position in the discharge outlet for the cooling zone and to open the discharge outlet extending to the powdering zone.

18. In a device for preparing printing plates, a support, a carriage movable over the support through powdering, heating and cooling zones and adapted to carry a plate to be treated in said zones, means for supplying air to said zones and comprising conduits leading to the respective zones and having valves for controlling the passage of air through said conduits, operating mechanism connected to said valves, means on the carriage engageable with said mechanism when the carriage is moved from the heating zone to the cooling zone to operate the same for opening the valve in the conduit to the cooling zone and closing the valve in the conduit to the powdering zone and also closing the valve in the conduit to the heating zone, said means on said carriage also operating said mechanism when the carriage is moved from the cooling zone to the powdering zone to close the valve of the conduit to the cooling zone and opening the conduits to the powdering and heating zones, said means on said carriage being inoperative on the mechanism when the carriage is moved from the powdering zone to the heating zone whereby the condults to the cooling and heating zones remain respectively closed and open when the carriage is moved from the powdering to the heating zones.

19. In a device for preparing printing plates, a support, a carriage movable on the support from a powdering chamber to a heating space and adapted to carry a plate to be treated in said chamber and space, means for applying powder to the plate in the powdering chamber and comprising a nozzle extending into said chamber adjacent the path of movement of the surface of the plate. and a brush acting upon the surface of the plate when the carriage is moved from the powdering chamber to remove surplus powder from the surface of the plate.

20. In a device for preparing prlnting plates, a support, a carriagemovable on the support from a powdering chamber to a heating space and adapted to carry a plate to be treated in said chamber and space, means for applying powder to the plate in the powdering chamber and comprising a nozzle extending into said chamber adjacent the path of movement of the surface of the plate, a brush acting upon the surface of the plate when the carriage is moved from the powdering chamber to remove surpluspowder from the surface of the plate, a second nozzle having its discharge end adjacent to the surface of the brush and operable to lt) lowhofi' particles of powder adhering to the rus 21. In a device for preparing printing of the plate when the carriage is moved from the powdering chamber to remove surplus powder from the surface of the plate, means for rotating the brush, and a second nozzle having its discharge end adjacent to the surface of the brush and operable to blow off particles of powder adhering to'the brush.

22. In a device for preparing printing plates, a support, a carriage movable on the support from a powdering chamber to a heating space and adapted to carry a plate to be treated in said chamber and space, means for applying powder to the plate in the powdering chamber and comprising a nozzle extending into said chamber adjacent the path of movement of the surface of the plate, a brush acting upon the surface of the plate when the carriage is moved from the powdering chamber to remove surplus powder from the surface of the plate, and means for adjusting the relation of the brush to the path of movement of the surface of the plate.

23. In a device for preparing printing plates, a support, a carriage movable on the support from a powdering chamber to a heating space and adapted to carry a plate to be treated in said chamber and space, means for applying powder to the plate in the powdering chamber, a nozzle extending into said chamber adjacent the path of movement of the surface of the plate, a brush acting upon the surface of the plate when the carriage is moved from the powdering chamber to remove surplus powder from the surface of the plate, a second nozzle having its discharge end adjacent to the surface of the brush and operable to blow off particles of powder adhering to the brush, and means for adjusting said second nozzle relative to the surface of the brush.

24. In a device for preparing printing plates, a support, a carriage movable on the support from a powdering to a heating zone and adapted to carry a plate to be treated in said zones, means for applying powder to the surface of the plate, a blowing means for projecting the powder upon the surface of the plate, an exhaust device for removing the superfluous powder projected upon the plate, and a reservoir for the powder, said exhaust means conveying the superfluous powder into said reservoir, said blowing means being connected to the reservoir for receiving powder therefrom. p

25. In a device for preparing printing plates, a'support, a carriage movable on the support-from a powdering to a heating zone and-adapted to carry aplate to be treated in said zones, means for applying powder to the surface of the plate, a blowing means for projecting the powder upon the surface of the plate, an exhaust device for removing the superfluous powder projected upon the plate, a reservoir for the powder, said exhaust means conveying the superfluous powder into said reservoir, said blowing means being connected to the reservoir for receiving powder therefrom, and means in the connection between the reservoir and the blowing means for controlling the supply of powder to thelatter. e

26. In a device for preparing printing plates, a support, a carriage movable on the support from a powdering to a heating zone and adapted to carry a plate to be treated in said zones, meansfor applying powder to the surface of the plate, a blowing means for projecting the powder upon. the surface of the plate, an exhaust device for removing the superfluous powder projected upon the plate, a reservoir for the powder, said exhaust means conveying the superfluous powder into said reservoir, said blo'wing means being connected to the reservoir for receiving powder therefrom, and means in said reservoir for aiding in distributing the powder therein.

27. In a device for preparing printing plates, a support, a carriage movable on the support from a powdering to a heating zone and adapted to carry a plate ,tobe treated in said zones, means for applying powder to the surface of the plate, a blowing means for projecting the powder upon the surface of the plate, an exhaust device for removing the superfluous powder projected upon the plate, a reservoir for the powder, said exhaust means conveying the superfluous powder into said reservoir, said blowing means being connected to the reservoir for receiving powder therefrom, and a series of baflles in the reservoir for distributing the powder therein.

28. In a device for preparing printing plates, means for circulating powder used as a resist on plates to be treated, a plate supporting means adapted to be located in the pathof circulation of the powder, means for controlling the circulation of said powder, said circulating means comprising a as a resist on plates to be treated, a

powder reservoir having pervious portions as a resist on plates to be treated, a plate supporting means adapted to be located in the path of circulation of the powder, means for controlling the circulation of said powder, said circulating means comprising a powder reservoir having a series of per vious pockets for permitting the escape of air and the retentionof the powder.

30. In a device for preparing printin plates, means for circulating powder ulsed p ate supporting means adapted to be located in the path of circulation of the powder, means for controlling the circulation .of said powder, said circulating means comprising a powder reservoir having a series of pervious pockets for permitting the escape of air and the retention of the powder, and means for shaking the pockets for the shaking off of the powder adhering to the same.

. a 31. In a device for preparing printing plates, means for circulating powder used as aresist on plates to be treated, a plate supporting means adapted to be located in the path ofcirculation of the powder, means for controllingthe circulation of said powder, said circulating means com rislng a powder reservoir having a series 0 p'ervious pockets for permitting the escape of air and the retention of the powder, and means connected to the pockets and movable to contract and extend the pockets with a snap action whereby the powder adhering to the walls of the pockets may be forcibly cast therefrom.

32. Ina device for preparing printing plates, means for circulating powder used as a resist on plates to be treated, a plate supporting means adapted to be located in the path of circulation of the powder, means for controlling the circulation of said powder, said circulating means comprising a powder reservoir, feeding means in the reserervoir operable to feed the collected powder therein to the controlling means.

33. In a device for preparing printing plates, means for circulating powder used as a resist on plates to be treated, a plate supporting means adapted to be located in the path of circulation of the powder. means for controlling the circulation of said powder, said circulating means comprising a powder reservoir, feeding means in the reservoir operable to feed the collected powder therein to the controlling means, said feeding means having reverse feeding elements for stirring the powder and preventing packing thereof.

34. In a device for preparing printing plates, means for circulating powder used Hill an a resist on plates to be treated, a plate supporting means adapted to be located in the path of circulation of the powder, means for controlling the circulation of said powder, said circulating means comprising a powder reservoir, feeding means in the reservoir operable to feed the collected powder therein to the controlling means, said feeding means comprising feed screw for feeding the powder in one direction and a reverse feed portion at the end of the feed screw for stirring the powder and preventing packing thereof.

35. In a device for preparing printing plates, means for circulating powder used as a resist on plates to be treated, a plate supporting means adapted to be located in the path of circulation of the powder, means for controlling the circulation of said powder, said circulating means comprising a powder reservior, feeding means in the reservoir operable to feed the collected powder therein to the controlling means, said feeding means comprising a feed screw for feeding the powder in one direction and a reverse feed portion at the end of the feed screw for stirring the powder and preventing packing thereof, said reverse feed portion having notches for the passage therethrough of the powder in a direction opposite to the action of the reverse feed portion whereby the powder is stirred and prevented from packing but at the same time progresses through the notches for circulation.

36. In a device for preparing printing plates, a movable support for supporting plates to be treated and comprising a turntable upon which the plate may rest when powder is supplied to the surface of the plate, means for turning the table for supplying of the powder at a different direction than previously.

37. In a devicefor preparing printing plates, a movable sup ort for supporting plates to be treated an comprising a turntable upon which the plate may rest when powder is supplied to the surface of the plate, means for turning the table for supplying of the powder at a different direction than previously, a race-way on the support and rollers carried by the table and cooperating with the race-way for ready turning of the table on the support.

38. In a device for preparing printing plates,- a movable support for supporting plates to be treated and comprising a turntable upon which the plate may rest when powder is su plied to the surface of the plate, means or turning the table for supplying of the owder at a different direction than previous y, said table and support having coo erable lockin elements for holding the tab e in turned re ation.

39. In a device for preparing printing plates, a movable support for. supporting plates to be treated and comprising a grate upon which the plate may rest when powder is supplied to the surface of the plate, the surplus powder being capable of passing through the openings of the grate, a turntable upon which the plate may rest when powder is su plied to the surface of the plate, means or turning the table for supplying of the powder at a different direction than previously, said table and support having cooperable recesses and spring pressed balls for normall holding the table in turned relation to the support.

40. In a device of the character disclosed, a heating chamber, movable means for carrying a plate to be treated and movable into and from said chamber, heating means in the chamber located to transmit heat to the powdered surface of the plate when carried into the chamber, means engaged by the movable means when it has moved into the chamber to effect transmission of heat from the heating means and when starting to move from said chamber to efiect a cuttingolf of said heat.

41. In a device of the character disclosed, a heating chamber, movable means for carrying a plate to be treated and movable into and from said chamber, heating means in the chamber located to transmit heat to the surface of the plate when carried into the chamber, and comprising burners, a pilot light in the chamber arranged to ignite the burners, means for supplying a combustible .medium to the burners, means on the supplying means and engageable by the movable means when moved into the chamber to effect the supply of the medium to the burners and when the movable means is moved from the chamber to effect a cut-0E of said medium.

42. In a device of the character disclosed, a heating chamber, means for supporting a plate therein for treatment of the surface thereof, burners located above said surface of said plate, means forsupplying a supporter o combustion to said burners and over said plate, said chamber being open at the lower portion thereof for the free exit of the products of combustion.

43. A method of treating printing plates or the like, comprising the steps of projecting a sheet of resist material upon the sur face of a plate and at an acute angle tosaid surface, subjecting said surface of said plate to heat for a short period of time sufficient to only heat and fix the resist material, and subjectin the surface of the plate to a stream 0 air for cooling the same.

44. A method of treating printing plates or the like, comprising the steps of circulating a stream of air and resist material, and moving a plate to be treated through said surface of said p ate, controlling the circulation to effect a pro ection of said material upon said surface of the plate while the plate is being moved through the path of circula tion, and for cutting off the circulation of the material when the plate has moved out of said path, and then fixing the material on said surface. 7

46. A method of treating printing plates or the like, comprisin the directing of a stream of air and resist powder upon the surface of a plate to be treated, applying a brush to the surface of the plate for removing su erfluous particles of the powder, and then ing the remaining powder on said surface of the plate.

47. In a device for preparing printing plates, a support, a carriage movable on the support from a powdering to a heating zone and adapted to carry a plate to be treated in said zones, means for applying powder to the surface of the plate and comprising a blowin means for projecting the powder upon the surface of the plate, an exhaust device for removing the superfluous powder projected upon the plate, a reservoir for the powder, said exhaust means conveying the superfluous powder into said reservoir, said blowing means being connected to the reservo1r for receiving powder therefrom, and means in the connection between the reservoir and the blowing means for controlling the supply of powder to the latter, said connection having a relief valve for the inlet of air for clearing the passages in said connection, and blowing means of powder when the control means is closed.

48. In a device for preparing printing plates, means for circulating powder used as a resist on plates to be treated, a plate sup portin means adapted to be located in the path of the circulation of the powder, means for controlling the circulation of the powder, and air relief means connected to the circulating means and o crating to permit entry of air to clear the clrculating means of powder when control means is operated to stop circulation.

49. In a device for preparing printin plates, means for circulating powder use as a resist on plates to be treated, a plate supporting means adapted to be located in the path of the circulation of the powder, means for controlling the circulation of the powder, and an air relief valve connected to the controlling means for admitting air into the circulating means when the controlling means is shut ofl.

In witness whereof, I hereunto subscribe my name to this specification.

HERBERT H. POWERS. 

